It is well known in the welding art that when it is desired to join with a high strength weld two workpieces of substantial thickness, it may be necessary to utilize the so-called "deep fill" welding technique. Such deep fill welding includes the formation of the workpiece extremities to be joined in configurations defining a weld joint space between the workpieces and extending partially through the thicknesses of the workpiece. The presence of a weld joint space allows a deep satisfactory weld to be accomplished since the welding electrode may be inserted deeply between the workpieces to generate the requisite heat at such a location to promote weld penetration and complete fusion. In deep fill welding the depth of the weld joint space is substantially greater than its width.
Also, it is well known that in welds of substantial width and depth, a tendency for weld porosity occurs along the centerline of the weld. In order to minimize deleterious effect due to this phenomenon, it is possible in deep fill welds utilizing a weld joint space to include pilot means in the weld joint configuration that result in the weld parting line extending from the finished weld tangentially from the weld root rather than coaxially along the long axis of the weld. Such pilot means also aid in the positioning of the workpieces prior to welding.
Despite these advantages, deep fill welds sometimes fail and weld depths are limited by the difficulty in causing sufficient heat to collect at the corners of the root of the weld joint space. This can result in insufficient fusion at these corners, porosity in the weld and resultant stress risers that may initiate cracks leading to failure.
It is an object of this invention to provide a deep fill welding joint configuration, deep fill welding method and product resulting from such a method that retain all the advantages of conventional deep fill welding as detailed above, but also promote welds having depths not heretofore contemplated using commercially available arc welding equipment. Such extremely deep welds especially are useful in the fabrication of products of large metal thicknesses that are subject to large bending and twisting loads. An example of such a product is a drive axle housing included in heavy on and off highway vehicles.